TY - JOUR
T1 - Antioxidant activity assay based on laccase-generated radicals
AU - Nugroho Prasetyo, Endry
AU - Kudanga, Tukayi
AU - Steiner, Walter
AU - Murkovic, Michael
AU - Nyanhongo, Gibson S.
AU - Guebitz, Georg M.
N1 - Funding Information:
Acknowledgement This work was made possible by the support offered by the Austrian Academic Exchange Service (ÖAD) and European Union Biorenew Project [Sixth Framework Programme (FP6–2004-NMP-NI-4)]. This work is dedicated to Professor Herfried Griengl on the occasion of his 70th birthday.
PY - 2009/1
Y1 - 2009/1
N2 - A novel antioxidant activity assay was developed using laccase-oxidized phenolics. In a three-step approach, phenolic compounds were first oxidized by laccase. Laccase was then inhibited using 80% (v/v) methanol which also stabilized the oxidized phenolics which were then used to measure antioxidant activities of ascorbic acid and Trolox. From a number of laccase-oxidized phenolics screened for potential use in the measurement of antioxidant activities, syringaldazine emerged the best, giving results comparable to the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, which is currently used in conventional methods. Like DPPH radicals, two moles of stoichiometric oxidized syringaldazine were reduced by one mole of either ascorbic acid or Trolox. For the first time we show that antioxidant activity can be correlated to oxygen consumption by laccase. Reduction of one molecule of oxygen corresponded to oxidation of four molecules of syringaldazine which in turn is reduced by two molecules of Trolox or ascorbic acid. This study therefore demonstrates the great potential of using laccase-oxidized syringaldazine for the measurement of antioxidant activity.
AB - A novel antioxidant activity assay was developed using laccase-oxidized phenolics. In a three-step approach, phenolic compounds were first oxidized by laccase. Laccase was then inhibited using 80% (v/v) methanol which also stabilized the oxidized phenolics which were then used to measure antioxidant activities of ascorbic acid and Trolox. From a number of laccase-oxidized phenolics screened for potential use in the measurement of antioxidant activities, syringaldazine emerged the best, giving results comparable to the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, which is currently used in conventional methods. Like DPPH radicals, two moles of stoichiometric oxidized syringaldazine were reduced by one mole of either ascorbic acid or Trolox. For the first time we show that antioxidant activity can be correlated to oxygen consumption by laccase. Reduction of one molecule of oxygen corresponded to oxidation of four molecules of syringaldazine which in turn is reduced by two molecules of Trolox or ascorbic acid. This study therefore demonstrates the great potential of using laccase-oxidized syringaldazine for the measurement of antioxidant activity.
KW - Antioxidant assay
KW - Laccase-oxidized phenolics
KW - Syringaldazine
UR - http://www.scopus.com/inward/record.url?scp=57849085649&partnerID=8YFLogxK
U2 - 10.1007/s00216-008-2466-1
DO - 10.1007/s00216-008-2466-1
M3 - Article
C2 - 18958446
AN - SCOPUS:57849085649
SN - 1618-2642
VL - 393
SP - 679
EP - 687
JO - Analytical and Bioanalytical Chemistry
JF - Analytical and Bioanalytical Chemistry
IS - 2
ER -